A major trend in wearable devices is not only providing data to a user, but also sensing important information from a user. The user's eyes can provide critical information to help the user navigate through screens, monitor the health and alertness of the user, and provide feedback on reactions of the user to different sources of information. Eye monitoring commonly requires illumination sources, typically infrared lights, to be positioned in front of the eye. This front illumination adds devices and electrical connections to a highly visible part of eyewear, often limiting design aesthetics. Furthermore, the electrical connections can often pass through the hinge of the eyewear, and can result in the hinge becoming stiffer, reducing the reliability of the electrical connection, or both. There is a need for eye monitoring illumination systems to be positioned elsewhere on the eyewear.